Two sources of images for Tax Day Tea Party signs, MarshBaby & Simon Jester.
For those of you who are not SciFi fans, Simon Jester is reference to Robert Heinlein’s classic The Moon is a Harsh Mistress, which was the Monday Book pick on January 26, 2009.
2018 update: Both the sites referenced are no longer valid.
Tea Party gear can be found at http://www.shirts4freedom.com